Influence of pH, N, P, N: P Ratio, and Dissolved Inorganic Carbon on Ulva ohnoi Growth and Biomass Quality: Potential Implications in IMTA-RAS

Round 1

Reviewer 1 Report

The authors evaluate the culture a green seaweed, looking at differing nutrient situations in experimental RAS. Unfortunately, they used a non-endemic (although alga was collected in Spain) green alga. I suggest to add a paragraph to the introduction highlighting the reasoning of this selection (there must be arguments for not using an endemic species!) and provide some statement on the biosecurity (although biosecurity cannot be assumed by the use of a RAS alone! For example can spread be prevented using Ozone or UV disinfection?). Also, the authors put their investigation in the context of coculturing (IMTA) thee seaweed with sole. Here the introduction needs to be improved – why do you envision a coculture with sole and not – for example – sea bass? Since you did not include specific fish in your study (it is not an IMTA study!!) it is advisable to highlight the possibility to improve sustainability of aquaculture by coculturing in general and list possible candidates for IMTA. The introduction should be rewritten. Throughout the text the authors use experience instead of experiments.  

All authors need to review the manuscript. This could have improved the manuscript.

Mayor language editing is required!

 

 

L142: Details on the protocol and method need to be provided

L162: Again, methodology is not sufficiently described. How often did you assess parameters. Provide a graph.

What temperature? How did you control temperature?

 

 

L483: The best strategy to follow in an IMTA-RAS fish-macroalgae system is to maintain the highest levels of nitrogen for the algae

 

Sorry, but in an IMTA there are fish that reveal substantial impact of high nitrogen. Reformulate the sentence

 

Comments for author File: Comments.pdf

Author Response

Reviewer 1

The authors evaluate the culture a green seaweed, looking at differing nutrient situations in experimental RAS. Unfortunately, they used a non-endemic (although alga was collected in Spain) green alga. I suggest to add a paragraph to the introduction highlighting the reasoning of this selection (there must be arguments for not using an endemic species!) and provide some statement on the biosecurity (although biosecurity cannot be assumed by the use of a RAS alone! For example can spread be prevented using Ozone or UV disinfection?).

 In the introduction, a paragraph (lines 41 to 60) has been included where the non-native nature of Ulva ohnoi on European coasts is questioned and the main reasons for its choice for co-cultivation with sole, the most promising finfish species for the development of IMTA-RAS systems in the Iberian Peninsula.

Also, the authors put their investigation in the context of coculturing (IMTA) thee seaweed with sole. Here the introduction needs to be improved – why do you envision a coculture with sole and not – for example – sea bass?

Seabream and seabass are farmed in Iberia only offshore in floating cages.

 Since you did not include specific fish in your study (it is not an IMTA study!!) it is advisable to highlight the possibility to improve sustainability of aquaculture by coculturing in general and list possible candidates for IMTA. The introduction should be rewritten.

 The reviewer is right, this is not a true IMTA study even though the water used mimics the effluent from a fish farm in RAS. For this reason, the title has been changed and the introduction revised in depth.

 Throughout the text the authors use experience instead of experiments.

Throughout the text experience/s has been replaced by experiment/s

All authors need to review the manuscript. This could have improved the manuscript.

Mayor language editing is required!

The manuscript has been revised by all authors ann the language of it has been thoroughly revised

L142: Details on the protocol and method need to be provided

Done; see lines 175-181 in the new version of the manuscript

L162: Again, methodology is not sufficiently described. How often did you assess parameters. Provide a graph.

Done; see lines 202-214 in the new version of the manuscript

What temperature? How did you control temperature?

See lines 226-228 and 251-253 in the new version of the manuscript

L483: The best strategy to follow in an IMTA-RAS fish-macroalgae system is to maintain the highest levels of nitrogen for the algae. Sorry, but in an IMTA there are fish that reveal substantial impact of high nitrogen. Reformulate the sentence

See lines 575-579 reformulating the sentence

The small text changes suggested directly in the first version of the manuscript have also been made.

Reviewer 2 Report

The manuscript deals with a topic of Culture development of the seaweed Ulva ohnoi in IMTA-RAS systems: Influence of pH, N, P, N: P ratio, and dissolved inorganic carbon on growth and biomass quality. The story is interesting and attracting, the experimental design and the methodology are well performed. 

My comments are:

1- We didn't start in the abstract and keyword by abbreviation define it

2- In Material and method line 138, Write the conditions of sample preparations and analysis (Full protocol, apparatus conditions). In addition, write the country and city of elemental analyzer apparatus.

3- In line 156, Give more details for analysis; the company, country and city of the spectrophotometer used 

4- In line 168 What did you mean by two 100 L please check 

5- In line 172, %0 delete 0

6- In line 180, Why the authors didnt determine these elements (Fe, Mn, Zn, Co)

7- In discussion part Authors must update the references used with deep explanation and more improvments

8- author needs to add updated reference from last three years (2020-2022)

9- In conclusion add sentence about the application and the future vision of this work 

Author Response

1- We didn't start in the abstract and keyword by abbreviation define it

 Done

 2- In Material and method line 138, Write the conditions of sample preparations and analysis (Full protocol, apparatus conditions). In addition, write the country and city of elemental analyzer apparatus.

 Done

 3- In line 156, Give more details for analysis; the company, country and city of the spectrophotometer used

 Done

 4- In line 168 What did you mean by two 100 L please check

 Rewrited the sentence:”two tanks of 100 L were used”

 5- In line 172, %0 delete 0

 Is 34 ‰, the salinity units

 6- In line 180, Why the authors didnt determine these elements (Fe, Mn, Zn, Co)

 We use a commercial Provasoli medium with these elements

 7- In discussion part Authors must update the references used with deep explanation and more improvments

 Discussion

 8- author needs to add updated reference from last three years (2020-2022)

 The discussion has been revised and improved and some recent references are added in the manuscript

 9- In conclusion add sentence about the application and the future vision of this work

 This sentence has been added: A special interest of these IMTA-RAS systems with macroalgae is that 582 the algae could in the future perform the function of the current bacterial 583 filters necessary for the reduction of ammonium produced by fish.

Reviewer 3 Report

Comments for author File: Comments.pdf

Author Response

1. It is necessary to add the name of the axes in the figures (Figure 2-6, Figure 10-11).

Done, except in figures 10 (not necessary) and 11 because the y-axis has different values depending on the cases as specified in the legend.

2. Numbers must be separated by a point, not a comma

Done

3. Figure title 3, the authors indicate «Wet weight (gr)». It's probably more correct to indicate «Wet weight (g)

Done

4. References must be correct. Volume number should be written in italics.

Done

Round 2

Reviewer 1 Report

Some parts are difficult to understand and it would be desirable to get a native English speaker go through the text.

Reviewer 2 Report

The Authors improved their manuscript and made all suggestions